02.-Evolution-Biological-Communities-and-Species-Interactions (1)

Acclimation

When an individual organism can respond immediately to a changing environment.

Adaptation

The acquisition of traits that allow a species to survive in its environment.

Genetic traits

is passed from generation to generation and allow a species to live more successfully in its environment.

Evolution

the basic idea is that species change over generations because individuals compete for scarce resources.

Natural Selection

the process of better-selected individuals passing their traits to the next generation.

Mutation

changes to the DNA coding sequence of individuals that occurs occasionally, and the changed sequences are inherited by offspring.

Justus von Liebig

According to him, the single factor in shortest supply relative to demand is the critical factor determining where a species lives.

Victor Shelford

He stated that each environmental factor has both minimum and maximum levels, called tolerance limits, beyond which particular species cannot survive or is unable to reproduce.

Critical factor

The single factor closest to these survival limits is the ________ that limits where a particular organism can live.

Habitat

the place or set of environmental conditions in which a particular organism lives.

Ecological niche

describes both the role played by a species in a biological community and the set of environmental factors that determine its distribution.

Charles Elton

British Ecologist who defined the concept of niche in 1927. According to him, each species had a role in a community of species, and the niche defined its way of obtaining food, the relationships it had with other species, and the services it provided to its community.

G. E. Hutchinson

The American limnologist who, thirty years later, proposed a more biophysical definition of niche. According to him, every species exists within a range of physical and chemical conditions such as temperature, light levels, acidity, humidity, or salinity. It also exists within a set of biological interactions such as predators and prey present, defenses, or nutritional resources available.

Generalists

species that tolerate a wide range of conditions or exploit a wide range of resources. Example: Species that thrive in broad variety of environments such as weedy species or pests (rats, cockroaches, or dandelions).

Specialists

species that have a narrow ecological niche. Examples are Giant Panda and Giant Saguaro.

Speciation

The development of a new species

Allopatric speciation

speciation that occurs when populations are geographically separated.

Geographic isolation

when the habitat are far enough apart that population were genetically isolated; they couldn’t interbreed with populations on the other habitat.

Sympatric Speciation

speciation that occurs within one geographic area.

Behavioral isolation

when two identical species live in similar habitats but have different mating calls. This difference is enough to prevent interbreeding.

Directional Isolation

the shift toward one extreme of a trait.

taxonomy

The study of types of organisms and their relationships. With this, organisms can be traced which common ancestors they have descended

Binomials

also called Scientific or Latin Name

Competition

A type of antagonistic relationship within a biological community. Organisms compete for resources that are in limited supply such as energy and matter in usable forms, living space, and specific sites to carry out life’s activities.

Intraspecific competition

competition among members of the same species

Intraspecific competition

competition between members of different species

Predator

Any organism that feeds directly on another living organism, whether or not this kills the prey.

Symbiosis

Two or more species live intimately together, with their fates linked.

mutualism

type of symbiosis in which both members’ benefits.

commensalism

type of symbiosis in which one member clearly benefits and the other apparently is neither benefited nor harmed.

parasitism

a form predation may also be considered symbiosis because of the dependency of the parasite on its host.

endosymbiosis

one species living inside another one

Ectosymbiosis

one species living on the surface of the other species

Keystone species

Plays a critical role in a biological community that is out of proportion to its abundance.

Productivity

measure of biological activity

Abundance and Diversity

measure the number and variety of organisms

Resilience and stability

make communities resistant to disturbance

Primary productivity

The rate of biomass production. An indication of the rate of solar energy conversion to chemical energy.

Abundance

expression of the total number of organisms in a biological community

Diversity

measure of the number of different species, ecological niches, or genetic variation present.

inversely

The abundance of a particular species often is _______ related to the total diversity of the community.

ecological structure

refers to patterns of spatial distribution of individuals and populations within a community, as well as the relation of a particular community to its surroundings.

local level

At the ________, even in a relatively homogeneous environment, individuals in a single population can be distributed randomly, clumped together, or in highly regular patterns.

random-arranged populations

In _________, individuals live wherever resources are available.

Ordered patterns

_________may be determined by the physical environment but are more often the result of biological competition.

Robert MacArthur

a graduate student at Yale, proposed that the more complex and interconnected a community is, the more stable and resilient it will be in the face of disturbance.

Constancy

lack of fluctuations in composition or functions

Inertia

resistance to perturbations

Renewal

ability to repair damage after disturbance

edge effects

The boundary between one habitat and its neighbors is an important aspect of community structure. These relationships are called_________

ecotones

are what the ecologists call the boundaries between adjacent communities

closed community

a community that is sharply divided from its neighbors.

open community

a community with gradual or indistinct boundaries over which many species cross.

climax community

is the community that developed last and lasted the longest.

Ecological succession

is the history of community development. When a succession occurs, organisms occupy a site and change the environmental conditions.

Primary succession

Land that is bare of soil (a sandbar, mudslide, rock face, and volcanic flow) is colonized by living organisms where none lived before

Secondary succession

When an existing community is disturbed, a new one develops from the biological legacy of the old.

Ecological development or facilitation

In both kinds of succession, when organisms change the environment by modifying soil, light levels, food supplies, and microclimate, the change permits new species to colonize and eventually replace the previous species.

pioneer species

In primary succession on land, the first colonists (microbes, mosses, and lichens) that can withstand a harsh environment with few resources.

disturbance

Any force that disrupts the established patterns of species diversity and abundance, community structure, or community properties.

disturbance-adapted species

species that can survive periodic disturbance

Continuous introduction of new community members and the disappearance of previously existing species are requirements of succession.